Hydrocarbons, such as oil and gas, are commonly obtained from subterranean formations that may be located onshore or offshore. The development of subterranean operations and the processes involved in removing hydrocarbons from a subterranean formation typically involve a number of different steps such as, for example, drilling a wellbore at a desired well site, treating the wellbore to optimize production of hydrocarbons, and performing the necessary steps to produce and process the hydrocarbons from the subterranean formation.
After drilling a wellbore that intersects a subterranean hydrocarbon-bearing formation, a variety of wellbore tools may be positioned in the wellbore during completion, production, or remedial activities. It is common practice in completing oil and gas wells to set a string of pipe, known as casing, in the well and use a cement sheath around the outside of the casing to isolate the various formations penetrated by the well. To establish fluid communication between the hydrocarbon-bearing formations and the interior of the casing, the casing and cement sheath are perforated. Fracturing operations can then be performed through the perforated sections of the formation in order to increase the size of perforations and, ultimately, the flow rate of hydrocarbons from the formation to the surface of the wellbore.
In order to selectively expose certain portions of the formation along the length of the wellbore for perforation or fracturing operations, the casing can be equipped with one or more sets of sleeves disposed along an inner diameter of the casing. These sleeves can be slid out of the way to provide access to the formation at multiple different fracturing zones along the length of the wellbore. To slide the sleeves out of the way to expose a portion of the formation, an operator typically drops a ball down the wellbore, and the ball forms a plug along a decreased diameter portion of the sliding sleeve. The wellbore can then be pressurized against the plug to force the sleeve to slide downward, exposing the fracture zone of the wellbore.
In wellbores having multiple sets of sleeves for accessing different fracturing zones, the sliding sleeves can be actuated by incrementally dropped balls. Unfortunately, these dropped balls can form obstructions that must be milled out of the wellbore before a subsequent sliding sleeve can be actuated. This leads to lost time spent removing obstructions from the wellbore while performing multi-zone fracturing operations in the wellbore.